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oil casing pipe, casing pipe, oil casings, anti-corrosion method of oil casing

Company News

oil casing pipe, casing pipe, oil casings, anti-corrosion method of oil casing
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6 Effective Anti-corrosion Methods for Oil Casing Pipe

Date:2025-07-23View:19Tags:oil casing pipe, casing pipe, oil casings, anti-corrosion method of oil casing

oil casing pipe

The corrosion of oil casing pipe is the most important issue to be concerned about during use. Many studies have shown that more than 60% of the failure accidents of the pipe string are related to its corrosion behavior in the drilling fluid. Corrosion not only causes the casing pipe wall thickness to be thinned and reduces its bearing capacity, but may also cause safety problems such as leakage. Common types of corrosion include hydrogen sulfide, carbon dioxide stress corrosion damage, electrochemical corrosion, and epoxy mold corrosion. These types of corrosion may cause serious damage to oil casing pipe under specific geological and mining conditions.

 

Anti-corrosion treatment of oil casing pipe is a key measure to ensure its long-term stable operation in harsh underground environments. The following are some of the main anti-corrosion treatment methods:

 

1. Strict water quality management

Water quality meets the standard: First of all, it is necessary to ensure that the water quality in the injection well meets the standard and reduce the corrosion source introduced by water quality problems. This includes strengthening water quality testing and management, implementing cleaning and sewage injection, and strengthening the cleaning of the main water pipeline to ensure that the water quality in the station and at the bottom of the well meets the standard.

 

2. Sterilization treatment

Annulus protection fluid: For water injection wells that have been put into production, annulus protection fluid mainly for sterilization is regularly applied to inhibit bacterial growth and reduce bacterial corrosion. This practice should be institutionalized to ensure regular addition.

 

3. Physical protection

Rubber rings and centralizers: In view of the accelerated effect of mechanical abrasion on oil casing pipe corrosion, it is recommended to install rubber rings on the tubing couplings, or to install centralizers in areas with severe well deviation. This can effectively prevent the tubing from scratching the casing pipe during the operation and water injection process, and avoid long-term contact between the tubing and one side of the casing pipe, thereby reducing friction corrosion.

 

4. High-temperature sterilization

High-temperature water or water vapor: In view of the serious bacterial corrosion under the scale, and the characteristics of slow growth and easy killing of SRB (sulfate-reducing bacteria) at high temperatures, 100 degrees Celsius high-temperature water or water vapor can be regularly injected into the annulus to kill the SRB under the scale, thereby reducing bacterial corrosion.

 

5. Use cathodic protection and coated casing pipe with caution

Cathode protection: Cathodic protection is an electrochemical anti-corrosion method that prevents corrosion reactions by connecting a power source to the casing pipe to make it a cathode. The cathodic protection system usually includes a sacrificial anode and an impressed current system, in which the sacrificial anode corrodes and protects the casing pipe body, and the impressed current system further prevents corrosion through current.

 

Anti-corrosion coating: One or more layers of anti-corrosion coatings are applied to the surface of the oil casing pipe, such as epoxy powder coating, polyethylene coating, etc. These coatings can effectively isolate the contact between the corrosive medium and the casing pipe substrate, thereby playing an anti-corrosion role.

 

It is not recommended to promote the use of cathodic protection and coated casing pipe before the corrosion in the casing pipe of the water injection well is effectively controlled. This is because these two methods may not work effectively under certain conditions and may even aggravate corrosion.

 

6. Surface treatment and material selection

Surface treatment: Appropriately treat the surface of the oil casing pipe, such as sandblasting, cleaning, etc., to improve the adhesion and anti-corrosion effect of the coating.

 

Material selection: Use materials with good corrosion resistance to manufacture oil casing pipe, such as stainless steel pipes. Although the cost may be high, it can effectively extend the service life of the casing pipe.

 

Summary

In summary, the anti-corrosion treatment of oil casing pipe is a comprehensive process, which requires water quality management, sterilization, physical protection, high temperature sterilization, careful use of specific anti-corrosion methods, surface treatment and material selection, and anti-corrosion coating to ensure the long-term stable operation of the casing pipe in harsh environments.